This part of GB/T 16507 specifies the grades and standards of materials allowed to be used for pressure components of water tube boilers, the basic technical requirements for materials, the applicable range (temperature and pressure) and allowable stress of materials, and the allowed use of non-pressure components. The material grade and its standard. This part applies to the selection and use of materials for pressure components and non-pressure components of water tube boilers defined in the scope of GB/T 16507.1.